Power electronics cooling assemblies and methods for making the same

ABSTRACT

A power electronics module includes a heat sink structurally configured to dissipate thermal energy, an electrically-insulating layer directly contacting the heat sink, a conductive substrate positioned on and in direct contact with the electrically-insulating layer, a power electronics device positioned on and in direct contact with the conductive substrate, a printed circuit board layer that at least partially encapsulates the conductive substrate and the power electronics device, and a driver circuit component positioned on a surface of the printed circuit board layer.

TECHNICAL FIELD

The present specification relates to power electronics coolingassemblies and methods for making the same.

BACKGROUND

Power electronics devices embedded in printed circuit boards may beutilized in a variety of applications. For example, in vehicularapplications, printed circuit board embedded power electronics devicesmay be used to convert direct current (DC) into alternating current (AC)to power a motor. In such applications, power electronics devices may bethermally coupled to heat sinks and the like to dissipate heat from thepower electronics devices. However, conventional printed circuit boardembedded power electronics modules may include one or more intermediatelayers positioned between the power electronics device and the heatsink, which may impede the dissipation of heat from the powerelectronics devices.

SUMMARY

Accordingly a need exists for improved printed circuit board embeddedpower electronics modules that reduce thermal resistance between powerelectronics devices and a heat sink of the power electronics module.Printed circuit board embedded power electronics modules according tothe present disclosure generally include power electronics devices indirect contact with conductive substrates that are in direct contactwith an electrically-insulating layer. The electrically-insulating layeris in direct contact with a heat sink. The direct contact between theconductive substrates and the heat sink with the electrically-insulatinglayer minimizes intermediate components positioned between the powerelectronics devices and the heat sink, thereby minimizing thermalresistance between the power electronics devices and the heat sink. Byminimizing thermal resistance between the power electronics devices andthe heat sink, the amount of heat dissipated from the power electronicsdevices can be increased as compared to configurations includingintermediate components positioned between the power electronics devicesand the heat sink. By increasing the amount of heat that can bedissipated from the power electronics devices, the power electronicsdevices can be maintained at lower operating temperatures. Additionally,by increasing the amount of heat that can be dissipated from the powerelectronics devices, the power electronics devices can be operated athigher power outputs while maintaining a similar operating temperatureas compared to conventional configurations.

In one embodiment, a power electronics module includes a heat sinkstructurally configured to dissipate thermal energy, anelectrically-insulating layer directly contacting the heat sink, aconductive substrate positioned on and in direct contact with theelectrically-insulating layer, a power electronics device positioned onand in direct contact with the conductive substrate, a printed circuitboard layer that at least partially encapsulates the conductivesubstrate and the power electronics device, and a driver circuitcomponent positioned on a surface of the printed circuit board layer.

In another embodiment, a method for forming a power electronics moduleincludes positioning an electrically-insulating layer on a surface of aheat sink, positioning a conductive substrate on a surface of theelectrically-insulating layer opposite the heat sink, positioning apower electronics device on a surface of the conductive substrateopposite the electrically-insulating layer, positioning a printedcircuit board layer over the electrically-insulating layer, at leastpartially embedding the electrically-insulating layer, the conductivesubstrate, and the power electronics device, and positioning a drivercircuit component on a surface of the printed circuit board layeropposite the heat sink.

In yet another embodiment, a power electronics module includes a heatsink structurally configured to dissipate thermal energy, anelectrically-insulating layer directly contacting the heat sink, a firstconductive substrate in direct contact with the electrically-insulatinglayer, a second conductive substrate in direct contact with theelectrically-insulating layer and spaced apart from the first conductivesubstrate, a first power electronics device positioned on and in directcontact with the first conductive substrate, a second power electronicsdevice positioned on and in direct contact with the second conductivesubstrate, a conduit extending between and electrically coupling thefirst power electronics device and the second power electronics device,where the first conductive substrate and the second conductive substrateare positioned between the conduit and the electrically-insulatinglayer, and a printed circuit board layer that at least partiallyencapsulates first conductive substrate, the second conductivesubstrate, the first power electronics device and the second powerelectronics device.

These and additional features provided by the embodiments describedherein will be more fully understood in view of the following detaileddescription, in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The embodiments set forth in the drawings are illustrative and exemplaryin nature and not intended to limit the subject matter defined by theclaims. The following detailed description of the illustrativeembodiments can be understood when read in conjunction with thefollowing drawings, where like structure is indicated with likereference numerals and in which:

FIG. 1 schematically depicts a perspective view of a power electronicsmodule, according to one or more embodiments shown and described herein;

FIG. 2 schematically depicts a section view of the power electronicsmodule of FIG. 1 , according to one or more embodiments shown anddescribed herein;

FIG. 3 schematically depicts a perspective view of a heat sink of thepower electronics module of FIG. 1 , according to one or moreembodiments shown and described herein;

FIG. 4A schematically depicts a perspective view of the heat sink ofFIG. 3 and an electrically-insulating layer, according to one or moreembodiments shown and described herein;

FIG. 4B schematically depicts a front view of the heat sink and theelectrically-insulating layer of FIG. 4A, according to one or moreembodiments shown and described herein;

FIG. 5 schematically depicts a perspective view of the heat sink and theelectrically-insulating layer of FIG. 4A with one or more conductivesubstrates positioned on the electrically-insulating layer, according toone or more embodiments shown and described herein;

FIG. 6 schematically depicts a perspective view of the heat sink, theelectrically-insulating layer, the one or more conductive substrates,and one or more power electronics devices positioned on the one or moreconductive substrates, according to one or more embodiments shown anddescribed herein;

FIG. 7A schematically depicts a perspective view of the heat sink, theelectrically-insulating layer, the one or more conductive substrates,and the one or more power electronics devices at least partiallyembedded by a printed circuit board layer, according to one or moreembodiments shown and described herein;

FIG. 7B schematically depicts a section view of the power electronicsmodule of FIG. 7A along section 7B-7B of FIG. 7A, according to one ormore embodiments shown and described herein;

FIG. 8 schematically depicts a perspective view of the power electronicsmodule of FIG. 7B and a clamp, according to one or more embodimentsshown and described herein; and

FIG. 9 schematically depicts a perspective view of the power electronicsmodule of FIG. 7B and another clamp, according to one or moreembodiments shown and described herein.

DETAILED DESCRIPTION

Embodiments described herein are generally directed to power electronicsmodules including power electronics devices in direct contact withconductive substrates that are in direct contact with anelectrically-insulating layer. The electrically-insulating layer is indirect contact with a heat sink. The direct contact between theconductive substrates and the heat sink with the electrically-insulatinglayer minimizes intermediate components positioned between the powerelectronics devices and the heat sink, thereby minimizing thermalresistance between the power electronics devices and the heat sink. Byminimizing thermal resistance between the power electronics devices andthe heat sink, the amount of heat dissipated from the power electronicsdevices can be increased as compared to configurations includingintermediate components positioned between the power electronics devicesand the heat sink. By increasing the amount of heat that can bedissipated from the power electronics devices, the power electronicsdevices can be maintained at lower operating temperatures. Additionally,by increasing the amount of heat that can be dissipated from the powerelectronics devices, the power electronics devices can be operated athigher power outputs while maintaining a similar operating temperatureas compared to conventional configurations. These and other embodimentswill now be described with reference to the appended figures.

Referring initially to FIGS. 1 and 2 , a perspective view and a sectionview of a power electronics module 100 are schematically depicted,respectively. In embodiments, the power electronics module 100 generallyincludes a heat sink 110, an electrically-insulating layer 130, one ormore conductive substrates 140, one or more power electronics devices150, a printed circuit board layer 160, and one or more driver circuitcomponents 170.

Referring to FIGS. 2 and 3 , a perspective view of the heat sink 110 isschematically depicted. In embodiments, the heat sink 110 isstructurally configured to dissipate thermal energy. In someembodiments, the heat sink 110 is a cold plate 112 including an inlet116 and an outlet 118 through which cooling fluid can pass. For example,cooling fluid may enter the cold plate 112 through the inlet 116, mayflow through one or more fluid passageways 115 within the cold plate112, and may exit through the outlet 118. In embodiments, the heat sink110 includes one or more fins 120 positioned at least partially withinthe one or more fluid passageways 115 extending through the heat sink110. As the cooling fluid passes through the one or more fluidpassageways 115, the cooling fluid may contact the one or more fins 120,dissipating heat from the one or more fins 120, as described in greaterdetail herein. In embodiments, the one or more fins 120 may include anysuitable shape for transferring thermal energy to the cooling fluid, forexample and without limitation, plate fins, pin fins, wavy fins, or thelike.

Referring to FIGS. 2, 4A, and 4B, a perspective view and a front view ofthe heat sink 110 is depicted with the electrically-insulating layer130. In embodiments, the electrically-insulating layer 130 directlycontacts the heat sink 110. For example, in the embodiment depicted inFIG. 4B, the electrically-insulating layer 130 directly contacts asurface 122 of the heat sink 110. In some embodiments, theelectrically-insulating layer 130 defines one or more through holes 132that extend through the electrically-insulating layer 130. The one ormore through holes 132 assist in retaining the electrically-insulatinglayer 130 within the printed circuit board layer 160, as described ingreater detail herein. In some embodiments, the electrically-insulatinglayer 130 may define one or more fastener holes 135 that extend throughthe electrically-insulating layer 130. Mechanical fasteners, such asbolts or the like, can be inserted within the one or more fastener holes135 to couple components (e.g., a clamp 180 as shown in FIGS. 8 and 9 )to the electrically-insulating layer 130 and/or the printed circuitboard layer 160. In embodiments, the electrically-insulating layer 130is formed of a material that restricts the flow of electrical current,for example and without limitation, Alumina (Al₂O₃), Aluminum Nitride(AIN), Beryllium Oxide (BeO), or the like.

Referring to FIGS. 2 and 5 , a perspective view of the heat sink 110,the electrically-insulating layer 130, and the one or more conductivesubstrates 140 is schematically depicted. In embodiments, the one ormore conductive substrates 140 directly contact theelectrically-insulating layer 130. For example, in the embodimentdepicted in FIG. 5 , the one or more conductive substrates 140 arepositioned on a surface 134 of the electrically-insulating layer 130opposite the heat sink 110. In some embodiments, the one or moreconductive substrates 140 are spaced apart from one another on theelectrically-insulating layer 130. In this way, in some embodiments, theone or more conductive substrates 140 may be electrically isolated fromone another. While in the embodiment depicted in FIG. 5 the powerelectronics module 100 includes six conductive substrates 140, it shouldbe understood that this is merely an example, and power electronicsmodules 100 according to the present disclosure may include any suitablenumber of conductive substrates 140 positioned on theelectrically-insulating layer 130. In embodiments, the one or moreconductive substrates 140 may be formed of an electrically conductivemetal, such as copper or the like.

In some embodiments, the one or more conductive substrates 140 maydefine cavities 142 extending inwardly into the one or more conductivesubstrates 140. The one or more power electronics devices 150 (FIG. 1 )may be positioned at least partially within the cavities 142, asdescribed in greater detail herein.

For example and referring to FIGS. 2 and 6 , a perspective view of theheat sink 110, the electrically-insulating layer 130, the one or moreconductive substrates 140, and one or more power electronics devices 150is schematically depicted. The one or more power electronics devices150, in embodiments, may directly contact the one or more conductivesubstrates 140. For example, in some embodiments, the one or more powerelectronics devices 150 may be positioned within associated cavities 142of the one or more conductive substrates 140. In some embodiments, theone or more power electronics devices 150 are electrically coupled tothe one or more conductive substrates 140.

In some embodiments, the one or more power electronics devices 150 maybe coupled to the one or more conductive substrates 140 through anysuitable connection, for example and without limitation, a sinteredconnection, a soldered connection, a welded connection, or the like. Inembodiments, the one or more power electronics devices 150 may includeany suitable device a semiconductor device such as, but not limited to,an insulated gate bipolar transistor (IGBT), a reverse conducting IGBT(RC-IGBT), a metal-oxide-semiconductor field-effect transistor (MOSFET),a power MOSFET, a diode, a transistor, and/or combinations thereof. Insome embodiments, the power electronics device 150 may include awide-bandgap semiconductor, and may be formed from any suitable materialsuch as, but not limited to, silicon carbide (SiC), silicon dioxide(SiO₂), aluminum nitride (AlN), gallium nitride (GaN), and boron nitride(BN), and the like. In some embodiments, the power electronics device150 may operate at high current and under high temperatures, for examplein excess of 250° C.

Referring to FIGS. 2, 7A, and 7B a perspective view and a section viewof the heat sink 110, the electrically-insulating layer 130, the one ormore conductive substrates 140, the one or more power electronicsdevices 150, and the printed circuit board layer 160 is schematicallydepicted. With the one or more power electronics devices 150 positionedon and coupled to the one or more conductive substrates 140, the printedcircuit board layer 160 may be positioned over theelectrically-insulating layer 130, at least partially embedding theelectrically-insulating layer 130, the one or more conductive substrates140, and the one or more power electronics devices 150. In someembodiments, the printed circuit board layer 160 may include anysuitable material, for example and without limitation, laminates, cottonpaper, epoxy, woven glass, matte glass, polyester, or the like andcombinations thereof.

In some embodiments and as shown in FIG. 7B, the printed circuit boardlayer 160 may extend through the through holes 132, which may assist inbonding the printed circuit board layer 160 to theelectrically-insulating layer 130.

In some embodiments, the printed circuit board layer 160 may include aconductive surface 162 through which components positioned on theconductive surface 162 can be electrically coupled to one another. Forexample and referring to FIG. 2 , in some embodiments, one or moredriver circuit components 170 may be coupled to the conductive surface162 of the printed circuit board layer 160. In embodiments, theconductive surface 162 of the printed circuit board layer 160 may beformed of any suitable conductor, for example and without limitation,copper or the like. In the embodiment depicted in FIG. 2 , the powerelectronics module 100 comprises six driver circuit components 170,however, it should be understood that power electronics modules 100according to the present disclosure may include any suitable number ofdriver circuit components 170. In embodiments, one or more of the drivercircuit components 170 may be electrically coupled to one anotherthrough the conductive surface 162 of the printed circuit board layer160. The driver circuit components 170 may include any suitablecomponents or circuitry for controlling operation of the powerelectronics module 100.

In some embodiments and referring to FIG. 2 , the power electronicsmodule 100 includes one or more conduits 154 for electrically couplingthe one or more power electronics devices 150. In embodiments, theconduits 154, 154′, 154″, and 154′″ may be utilized to connect positive,negative, and/or ground connections to the one or more power electronicsdevices 150. In some embodiments, the power electronics module 100includes a conduit 154′ that extends between a first power electronicsdevice 150 and a second power electronics device 150 and electricallycouples the first power electronics device 150 to the second powerelectronics device 150. In some embodiments, the first power electronicsdevice 150 may be electrically coupled to the second power electronicsdevice 150 through the conduit 154′ and one or more of the conductivesubstrates 140. In embodiments, the power electronics devices 150 andthe conductive substrates 140 are positioned between one or more of theconduits 154, 154′, 154″, and 154′″ and the electrically-insulatinglayer 130. For example, in the orientation depicted in FIG. 2 , theconduits 154, 154′, 154″, and 154′″ are positioned above the powerelectronics devices 150. By positioning the power electronics devices150 between the conduits 154, 154′, 154″, and 154′″ and theelectrically-insulating layer 130, the power electronics devices 150 maybe positioned in direct contact with the conductive substrates 140, andthe conductive substrates 140 may be positioned in direct contact withthe electrically-insulating layer 130. Put another way, by positioningthe power electronics devices 150 between the conduits 154, 154′, 154″,and 154′″ and the electrically-insulating layer 130, the powerelectronics devices 150 may be positioned closer to theelectrically-insulating layer 130 (and accordingly the heat sink 110) ascompared to configurations in which the conduits 154, 154′, 154″, and154′″ are positioned between the power electronics devices 150 and theelectrically-insulating layer 130. While in the section view depicted inFIG. 2 the conduits 154, 154′, 154″, and 154′″ are shown connecting twoof the power electronics devices 150, it should be understood that someor all of the power electronics devices 150 of the power electronicsmodule 100 can be coupled to one another by conduits. Further, while inthe section view depicted in FIG. 2 the conduits 154, 154′, 154″, and154′″ are shown at different vertical positions above the powerelectronics devices 150, it should be understood that the conduits 154,154′, 154″, and 154′″ may be positioned at the same or at differentheights.

In embodiments, by positioning the power electronics devices 150 indirect contact with conductive substrates 140 that are in direct contactwith the electrically-insulating layer 130, thermal resistance betweenthe electrically-insulating layer 130 and the power electronics devices150 can be minimized. Further, by positioning theelectrically-insulating layer 130 in direct contact with the heat sink110, thermal resistance between the electrically-insulating layer 130and the heat sink 110 can be minimized, thereby minimizing thermalresistance between the power electronics devices 150 and the heat sink110. In this way, the amount of heat transferred from the powerelectronics devices 150 to the heat sink 110 can be increased ascompared to configurations including intervening layers between thepower electronics devices 150 and the conductive substrates 140, betweenthe conductive substrates 140 and the electrically-insulating layer 130,or between the electrically-insulating layer 130 and the heat sink 110.By increasing the amount of heat transferred from the power electronicsdevices 150, the power electronics devices 150 may be maintained at alower operating temperature. Alternatively, the power electronicsdevices 150 may operate at an increased power output as compared toconventional configurations while being maintained at a similaroperating temperature.

Referring to FIG. 8 in some embodiments, the power electronics module100 includes a clamp 180 that can be coupled to the heat sink 110, theelectrically-insulating layer 130 (FIG. 7B), and/or the printed circuitboard layer 160. The clamp 180, in embodiments, generally extends aroundthe heat sink 110, and may at least partially encapsulate the heat sink110. The clamp 180 may be coupled to the heat sink 110, theelectrically-insulating layer 130 (FIG. 7B), and/or the printed circuitboard layer 160 in any suitable manner, for example through mechanicalfasteners such as bolts. The clamp 180 may support the heat sink 110,the electrically-insulating layer 130 (FIG. 7B), and/or the printedcircuit board layer 160, and may resist torsional forces applied to theheat sink 110, the electrically-insulating layer 130 (FIG. 7B), and/orthe printed circuit board layer 160. While in the embodiment depicted inFIG. 8 the clamp 180 is shown as a planar structure, it should beunderstood that this is merely an example, and the clamp 180 may includeany suitable structure to resist torsional forces.

For example and referring to FIG. 9 , in some embodiments, the clamp 180may include a cross or X-shape coupled to opposing corners of the heatsink 110, the electrically-insulating layer 130 (FIG. 7B), and/or theprinted circuit board layer 160.

It should now be understood that embodiments described herein aregenerally directed to power electronics modules including powerelectronics devices in direct contact with conductive substrates thatare in direct contact with an electrically-insulating layer. Theelectrically-insulating layer is in direct contact with a heat sink. Thedirect contact between the conductive substrates and the heat sink withthe electrically-insulating layer minimizes intermediate componentspositioned between the power electronics devices and the heat sink,thereby minimizing thermal resistance between the power electronicsdevices and the heat sink. By minimizing thermal resistance between thepower electronics devices and the heat sink, the amount of heatdissipated from the power electronics devices can be increased ascompared to configurations including intermediate components positionedbetween the power electronics devices and the heat sink. By increasingthe amount of heat that can be dissipated from the power electronicsdevices, the power electronics devices can be maintained at loweroperating temperatures. Additionally, by increasing the amount of heatthat can be dissipated from the power electronics devices, the powerelectronics devices can be operated at higher power outputs whilemaintaining a similar operating temperature as compared to conventionalconfigurations. These and other embodiments will now be described withreference to the appended figures.

Having described the subject matter of the present disclosure in detailand by reference to specific embodiments, it is noted that the variousdetails described in this disclosure should not be taken to imply thatthese details relate to elements that are essential components of thevarious embodiments described in this disclosure, even in cases where aparticular element is illustrated in each of the drawings that accompanythe present description. Rather, the appended claims should be taken asthe sole representation of the breadth of the present disclosure and thecorresponding scope of the various embodiments described in thisdisclosure. Further, it should be apparent to those skilled in the artthat various modifications and variations can be made to the describedembodiments without departing from the spirit and scope of the claimedsubject matter. Thus it is intended that the specification cover themodifications and variations of the various described embodimentsprovided such modification and variations come within the scope of theappended claims and their equivalents.

It is noted that recitations herein of a component of the presentdisclosure being “structurally configured” in a particular way, toembody a particular property, or to function in a particular manner, arestructural recitations, as opposed to recitations of intended use. Morespecifically, the references herein to the manner in which a componentis “structurally configured” denotes an existing physical condition ofthe component and, as such, is to be taken as a definite recitation ofthe structural characteristics of the component.

It is noted that terms like “preferably,” “commonly,” and “typically,”when utilized herein, are not utilized to limit the scope of the claimedinvention or to imply that certain features are critical, essential, oreven important to the structure or function of the claimed invention.Rather, these terms are merely intended to identify particular aspectsof an embodiment of the present disclosure or to emphasize alternativeor additional features that may or may not be utilized in a particularembodiment of the present disclosure.

For the purposes of describing and defining the present invention it isnoted that the terms “substantially” and “about” are utilized herein torepresent the inherent degree of uncertainty that may be attributed toany quantitative comparison, value, measurement, or otherrepresentation. The terms “substantially” and “about” are also utilizedherein to represent the degree by which a quantitative representationmay vary from a stated reference without resulting in a change in thebasic function of the subject matter at issue.

It is noted that one or more of the following claims utilize the term“wherein” as a transitional phrase. For the purposes of defining thepresent invention, it is noted that this term is introduced in theclaims as an open-ended transitional phrase that is used to introduce arecitation of a series of characteristics of the structure and should beinterpreted in like manner as the more commonly used open-ended preambleterm “comprising.”

What is claimed is:
 1. A method for forming a power electronics module,the method comprising: positioning an electrically-insulating layer on asurface of a heat sink; positioning a conductive substrate on a surfaceof the electrically-insulating layer opposite the heat sink; positioninga power electronics device on a surface of the conductive substrateopposite the electrically-insulating layer; positioning a printedcircuit board layer over the electrically-insulating layer, at leastpartially embedding the electrically-insulating layer, the conductivesubstrate, and the power electronics device; and positioning a drivercircuit component on a surface of the printed circuit board layeropposite the heat sink.
 2. The method of claim 1, wherein the powerelectronics device is a first power electronics device, the methodfurther comprising electrically coupling the first power electronicsdevice to a second power electronics device with a conduit extendingbetween the first power electronics device and the second powerelectronics device, wherein the first power electronics device and thesecond power electronics device are positioned between the conduit andthe electrically-insulating layer.
 3. The method of claim 1, furthercomprising coupling a clamp to the printed circuit board layer, whereinthe clamp extends around the heat sink.
 4. The method of claim 3 whereinthe clamp at least partially encapsulates the heat sink.
 5. The methodof claim 1, wherein positioning the printed circuit board layer over theelectrically-insulating layer comprises positioning printed circuitboard material within a through hole extending through theelectrically-insulating layer.
 6. The method of claim 1, wherein thedriver circuit component is a first driver circuit component, andwherein the method further comprises positioning a second driver circuitcomponent on the surface of the printed circuit board layer andelectrically coupling the first driver circuit component to the seconddriver circuit component.